Apparatus for continuously fabricating three-dimensional filament reinforced foam insulation

ABSTRACT

A method and apparatus for continuously fabricating three-dimensional (3D) filament reinforced foam insulation slabs. Rows of X or longitudinal filaments are fed longitudinally into a machine in spaced, stacked horizontal planes. Rows of Y or transverse filaments are fed transversely into the machine in spaced, stacked horizontal planes. Z or vertical filaments are fabricated into units of four vertical spaced lengths of strands which fit into each of the vertical column squares formed by the X-Y filaments to form the continuous X-Y-Z orthogonal array. Urethane or equivalent foam is discharged onto a moving belt beneath the filamentary array which is moved in the same direction and at the same rate as the belt carrying the foam. The foam material froths or foams upwardly through the filamentary array as they move along to the next station for curing. After sufficient cure, the foamed array is cut from the frames and into desired length, forming planks.

This is a division of application Ser. No. 669,819, filed Mar. 24, 1976,now U.S. Pat. No. 4,079,106, which is a continuation-in-part ofapplication Ser. No. 516,412, filed Oct. 21 1974, now abandoned.

BACKGROUND OF THE PRESENT INVENTION

Urethane foam that is orthogonally reinforced with filaments is aneffective cryogenic insulation. One use of such insulation is ininsulating compartments or holds of marine vessels used to transportliquid natural gas. Transporting natural gas in its liquid state (atcryogenic temperatures) is preferable to transporting it in its gaseousstate since it is reduced in volume approximately 600 times.

In one form, a metal storage tank is spaced from the hull of the vesseland insulation is applied to the inside of the tank. The Z fibers in thefoam insulation planks are bonded to sheets of plywood bolted to thetank, or the fibers may be bonded directly to the tank inner walls. Thelayered X-Y fibers of adjacent planks are bonded together to form aunitary contiguous insulation blanket that serves to contain the liquidnatural gas.

Heretofore, 3D reinforced foam insulation was made in block form inintermittent steps. One such method is disclosed in U.S. Pat. No.3,778,492 which issued to C. R. Lemons on Dec. 11, 1973 for Fabricationof Three-Dimensional Reinforced Foam Insulation Blocks. By this method,reinforcing filaments are attached to cardboard frames or strips whichare subsequently stacked and arranged over a pan in which the raw foambatter is placed. The foam then rises through the filamentary array.After the foam is cured, the cardboard is cut away (and discarded) andthe remaining foam block is bonded to similar blocks when used as aninsulation material. The non-productive cardboard frames and the batchprocess method of arraying the filaments and foaming are expensive,time-consuming and wasteful of material.

U.S. Pat. No. 3,972,554 to Muskat et al, discloses a continuous methodof producing fiber reinforced foam pads by impregnating batts ofrandomly arranged fibers with resin. Disclosures of a similar nature arefound in U.S. Pat. Nos. 3,273,978 to Paul and 3,867,494 to Rood, thelatter patent disclosing orientation of the fibers in layers. In thelatter case, the fibers have a tendency to deteriorate or exfoliatealong the planes of reinforcement.

However none of the above patents teaches continuous production of afoamed array of reinforcing fibers which are oriented in the X, Y and Zdirection according to the present invention.

SUMMARY OF THE PRESENT INVENTION

In accordance with the present invention an apparatus is provided forconstructing an X-Y-Z reinforced multi-layered array of filaments whichis embedded in foam insulation in a continuous process. The resultinginsulation planks preferably are of a specific width (24 inches) andthickness (4, 6 or 8 inches) but are of an infinite length. Presentpractice employed in using the invention is to cut the infinite length,endless insulation plank output into 10 foot lengths to facilitatehandling, shipping and ultimate installation.

The apparatus includes a machine for feeding X filaments longitudinallyand Y filaments transversely along a path of travel for each desiredlayer of filament reinforcement. The Y filaments may be held betweententer hooks, clips, or pins mounted on channel-like plates which rideon side rails for the length of the machine. Other Y filament retentionapparatus may be substituted, if desired. The Y filaments may be aboveor below or alternated above and below the X filaments for each or anydiscrete layer. The X and Y filaments may or may not be attached attheir cross-over points.

The Z filaments are continuously fabricated in long chains on anintegral, auxiliary portion of the machine. These filaments are lengthsof initially parallel strands held a discrete distance apart, then, atdiscrete intervals, brought together for bonding or otherwise attachingthe impregnated or pre-impregnated filaments together to form alternategrouped and spaced segments or bundles of strands, and subsequentlycured. These units of Z filaments are then machine-inserted into thevertically stacked squares formed by the X-Y filaments to form the X-Y-Zorthogonal array. Preferably, each X-Y grid has 3/8 inch openings andthe grids are vertically spaced 3/8 inch apart. In other embodiments,the width, thickness and length of the planks may be varied as well asthe size of the grid openings and their vertical spacing.

A standard mixing and metering machine is used to meter and mix theurethane or equivalent foam correctly and to discharge it onto a movingbelt beneath the filamentary array. Both the array and belt supportingthe foaming material move in the same direction and at the same rate.The lower moving belt of foam is then brought into close proximity tothe filamentary array, and the foam material froths upwardly through thefilamentary array.

Sufficient distance is incorporated in the length of the belts or chainsto insure sufficient curing of the foamed array to permit cutting andsubsequent handling. Vents for the removal of volatiles, and heaters orcooling means to control cure may be incorporated in conjunction withthis portion of the machine. After sufficient cure, the foamed array iscut from the tenter frames, chains, or belts, and cut to the approximatedesired length.

The tenter frames, chains, and belts are then cleaned, mechanically orwith heat or solvents, coated with a wax or an equivalent release agent,and automatically returned to the initial portion of the machine. Theprocess is therefore continuous and automatic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified schematic, perspective illustration showing thepresent apparatus used for making continuous 3D reinforced foaminsulation;

FIG. 2 is an enlarged, fragmentary, partially schematic perspectiveillustration of the apparatus used in making stacked X-Y filament grids;

FIG. 3 is a further enlarged perspective illustration of apparatus usedin arraying one form of continuous Z strands;

FIG. 4 is a fragmentary, pictorial representation of means on theendless belts for engaging the Z strands to bring them together atspaced intervals;

FIG. 5 is a fragmentary pictorial representation of the means in FIG. 4gripping the strands between the separation strips to bring themtogether;

FIG. 6 is a pictorial representation of continuous Z strands formingalternately grouped and spaced apart segments;

FIG. 7 is a partially schematic, pictorial illustration of apparatus forinserting the Z strand segments into the X-Y array;

FIG. 7a shows apparatus for moving the Z insertion apparatus of FIG. 7longitudinally during longitudinal movement of the X-Y array; and

FIG. 8 is an isometric fragmentary view of a typical three-dimensionalfilamentary array prior to the foaming operation.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT

A typical three-dimensional reinforced insulation plank is 24 incheswide and four inches, six inches, or eight inches thick. Although formedinto a plank of continuous infinite length, it is usually cut intoten-foot lengths for handling. In one example, layers of X orientedfibers extend longitudinally throughout the plank length, with thefibers spaced 3/8 inch apart. Layers of Y oriented fibers extendtransversely across the width with the fibers spaced 3/8 inch apart. Alayer of X and a layer of Y fibers (X and Y denoted longitudinal andtransverse directions) form a grid of 3/8 inch squares. A plurality ofsuch grids are vertically spaced over each other and also 3/8 inchapart. This forms vertically stacked X-Y squares into which one or morevertical or Z oriented fibers is inserted to form an X-Y-Z orthogonalarray. Preferably the fibers are bonded together at their cross-overpoints of contact. If the fibers have been pre-impregnated, i.e., coatedwith a resin, the bonding may be accomplished by simply heating at about180° F. for 10 to 15 seconds. If the fibers have not been previouslycoated, they might be sprayed or dipped into a resin after the array hasbeen formed, and then heated to bond the fibers together where theycontact each other.

After the X-Y-Z array has been formed, a urethane or equivalent formablematerial is then foamed through the array to embed or encapsulate itwithin the foamy material. When the foaming action has been completedand the resultant material solidified or cured so it can be handled, thematerial is cut from the apparatus holding the array in place, and thencut into planks for convenient handling, shipping, and installing foruse. These three-dimensionally reinforced insulation planks, as well ascertain apparatus used in their fabrication, form the subject matter ofother inventions whereas the present invention is concerned with theapparatus exemplified as set forth hereinafter.

One form of apparatus used in making three-dimensional reinforcedinsulation material is shown in FIG. 1. The X-Y array is made first,then the Z fibers are added to the matrix. Thereafter, the foamingoperation is performed, followed by curing and cutting. The apparatus inFIG. 1 will be explained in that order. Here there is shown banks 10 ofspools 12 on which are wound fibers 14 which are used in making the X-Ygrids. As each spool is emptied, it is replaced and the fibers from thenew spool joined to the end of the old spool fibers to form acontinuous, endless strand. X fibers are fed through X feed stations 16of which there is a station for each layer of grid of X fibers in thearray. At this station the X fibers are spaced laterally across thedesired width of the plank to be formed to provide a longitudinal planeof fibers. For a six inch thick array with 3/8 inch spacing, 17 suchstations are used. For a 24 inch wide array with 3/8 inch spacing, 65strands are fed into each station. Thus, 1105 spools 12 are incontinuous use for making the X fibers in the array. The dimensionsabove noted are typical but not limiting upon the practice of thisinvention.

Each layer of Y fibers in the array also has a Y fiber feed station 18.For a six inch thick array 17 spools are needed, one for each layer of Yfibers. The Y fibers are fed back and forth across the width of thearray and are hooked or looped over moving pegs or hooks on the sides,this structure to be hereinafter more fully described. The first X-Ystations 16, 18, make the lowermost layer, the second stations make thenext higher, the third stations make the next higher, etc., with thelast stations making the uppermost layer.

The vertically stacked X-Y array next passes along a pathway through anX-Y bonding station 20 where the X-Y fiber cross-overs are bonded. Thismay be done by spraying them with a resin and heating or by bonding theimpregnated or pre-impregnated filamentary material of the fibers in anynumber of well known methods. Simply heating to about 180° F. for 10 to15 seconds usually is sufficient for this purpose.

The vertical Z fibers which protrude through the vertically spaced X-Ysquares require 64 spools 22 from Z spool bank 24, based upon theinsertion of one fiber into each square and further based upon insertionin one laterally extending row of squares at a time. Each row of squaresreceiving Z fibers at the same time requires a separate Z insertionstation fed from 64 spools of filament material. In this illustrativeembodiment, where four strands are used to make a string of Z fibersegments for insertion into each square, four times that number ofspools is required.

From Z bank 24 the strands pass through a Z fiber fabrication station 26where four spaced strands of resin-impregnated glass filaments aresqueezed and bonded together at predetermined spaced intervals, forminga continuous chain of alternate grouped and spaced segments or bundles,of strands. After forming, these segments 28 are held in place betweenendless belts 30 and passed through a Z fiber curing station 32 wherethe segments become stiff with cured resin. One method of forming suchsegments is explained more fully hereinafter when reference is had toFIG. 3.

From the curing station 32 the chains of Z segments 28 are fed to a Zfiber insertion station 34 which is positioned downstream from the X-Yarray bonding station 20. In the embodiment shown these segments 28 passoverhead over rollers 36, 38 mounted on brackets 40 suspended from theceiling, not shown. At the Z fiber insertion station 34 the segments 28are fed into the vertical square columns of the X-Y array and cut fromits chain so the next segment can be inserted into the next column. Thisoperation will be more fully described hereinafter with reference toFIG. 7.

As the X-Y columns are filled with Z fibers, the array moves through anX-Y-Z bonding station 42 where the contacting portions of the Z fibersare bonded to the X-Y fibers to complete the array. This may be done ina manner similar to that performed at bonding station 20. In some casesthe bonding of the Z fibers to the X-Y array has been found to be anunnecessary step. In others the bonding is preferable. In any event,when the X-Y-Z array passes from bonding station 42 it is ready for thefoaming and encapsulation operation.

At foaming station 44, suitable chemicals for producing a foaminsulation are applied to the array. These chemicals may be theinsulative material in liquid form, an activator to causesolidification, and a blowing agent to cause the material to foam upthrough the array before solidification occurs. Polyurethane,appropriate catalyst and a Freon gas are examples of such chemicals.These chemicals are pumped from supply tanks 46, through control station48 and onto a moving belt 50 which moves at the same rate as the fiberarray. The urethane or equivalent foam material foams up through thearray. An endless belt 52 is positioned above the array to prevent thefoam moving the array upwardly as it passes through the array. It alsolimits upward expansion of the foam beyond the limits of the array whichit encapsulates. Both belts 50 and 52 are of such length that theysupport the moving foamed array until the foam has solidified and curedsufficiently for cutting and further handling. Curing is a function oftime with most of the chemicals used.

After sufficient curing, the foamed array 54 is then separated from itssupports such as side frames to which the Y fibers were attached (shownin FIG. 2), and the belt 50 on which it has been carried. Band saws 56with blades 58 trim the sides and saw 60 cuts the reinforced foaminsulation into planks 62 of desired length. These planks may then bewrapped or packaged if desired prior to subsequent curing or handling.The frames and belts used in moving the array and insulation materialare cleaned and returned to the initial portion of the machine forreuse. The entire system may be automated with an operator at controlstation 64 coordinating the various operations for continuous outputflow. Continuous non-stop movement of the array and foam material is thepreferred mode, according to the present invention.

Certain parts of the apparatus in FIG. 1 will now be explained ingreater detail. In FIG. 2 there is shown a portion of the X-Y arrayfabrication apparatus. Here elevated guides 66 extend horizontallybetween supports 68. These guides are C-shaped channels which receiverollers 70 on side frames 72. These side frames 72 are spaced apart sothat multiple layers of spaced X oriented fibers may pass between andparallel to the side frames. These side frames 72 have opposed verticalfaces 74 on which are mounted vertically spaced horizontal rows oftenter hooks 76. In one embodiment the horizontal row are 3/8 inch apartand the hooks are 3/8 inch apart in each row. These hooks extendinwardly to receive the transverse Y strands that pass from side frameto side frame in forming multiple layers of spaced Y oriented fibers forthe X-Y array.

The first or lowermost layer of spaced X fibers 78, from the spools 12in FIG. 1, are spaced across the width of the array and pass underguides 80 at X feed station 16 to move in a longitudinal direction shownby arrow 82. Guides 80 extend across the width of the array and aremounted on guides 66 by means of L-shaped brackets 84 having a supportplate 86 and downwardly extending leg 88. This structure is identical ateach of the X feed stations 16. However, the next X station 16A israised 3/8 inch to provide a second layer of X fibers 3/8 inch above thefirst layer. This is accomplished by placing a 3/8 inch block 90 undersupport plate 86 at this station. Subsequent X feed stations 16B, 16C,etc., are also raised with additional blocks until the desired thicknessor number of layers in the array is achieved. Thicker or thinner blocksmay be used to vary the vertical spacing as desired.

The Y feed stations 18 are mounted on guides 66. A feeder mechanism 92moves transversely between the side frames 72 to lace a Y strand betweententer hooks 76 on each side of the array. Each feed station laces thehooks on a selected plane, starting with the lowermost in the X-Y array.The next Y feed station 18A laces Y strands in the next higher layer andthe following feed station 18B laces Y strands in the next higher plane.The number of stations used depends upon the number of Y fiber layersdesired in the array.

FIG. 3 illustrates one form of mechanism that may be used to make Zsegments of the type shown in FIG. 6. These are lengths of initiallyparallel strands of filaments brought together at spaced intervals toform alternate grouped and spaced segments or bundles of strands. Eachbundle is inserted into the vertically spaced squares formed by X-Yfiber intersections in each layer of the array. One form of apparatusfor doing this is shown in FIG. 7, to be described hereinafter.

Referring now to FIG. 3 the Z fiber fabrication station 26 includes atable or bench 94 having two spaced upstanding guides 96 mountedthereon. These guides have a plurality of apertures 98 through which Zfibers pass to set up two vertical planes 100 of spaced fibers. Verticalspacers 102, 104 on an endless belt 106 pass between the vertical planesof fibers to maintain their spaced relationship, except at spacedintervals wherein two fibers from one plane are joined together with twofibers from the other to make a segment of four strands.

The two vertical planes 100 of fibers pass between a pair of endlessbelts 30. The belts are counterrotating as shown by arrows 108, 110 onrollers 112, 114. These belts have a plurality of opposed gripping bars116, 118 mounted thereon. The purpose of the opposed gripping bars 116,118 is that when they come together where their carrier belts 30 areparallel, they squeeze the parallel planes 100 of fibers together attheir points of contact. This squeezing together occurs between spacers102, 104 which keep the planes 100 of fibers spaced apart except wherethe gripping bars 116, 118 squeeze them together. This will be morefully explained when reference is had to FIGS. 4 and 5.

As the planes 100 of fibers pass between endless belts 30 they pass intothe Z fiber cure station 32 where the contacting fibers are bondedtogether. As the Z segments are returned from the cure station 32 theypass upwardly, over rollers 120 on support 122 on table 94. Thisseparates them from spacers 102, 104 between which fibers from the twoplanes 100 had been bonded. From rollers 120 the Z segments 28 move inthe direction of arrow 124 to the Z fiber insertion station 34 in FIG. 1which will be more fully described hereinafter when reference is had toFIG. 7.

Reference is now made to FIGS. 4, 5 and 6 for a further explanation asto how the Z segments 28 are formed. Although many strings of thesesegments are made at the same time with the apparatus in FIG. 3, onlyone string is made with the gripping bars 116, 118 shown in FIGS. 4 and5. In FIG. 4 rollers 112, 114 rotate counter to each other as shown byarrows 110, 112 to bring gripping bars 116, 118 on spaced belts 30together. Bar 116 has spaced side plates 126 which receive bar 118 inbetween, as shown in FIG. 5, when that portion of belts 30 are moving inspaced parallel relationship toward the curing station 32, shown in FIG.3. Side plates 126 have notches defined by edges 128 which capture twofibers 130 from one of the vertical planes 100 of Z fibers, shown inFIG. 3. As roller 112 rotates, fibers 130 ride along edges 128 to theirapex 132. Gripping bar 118 also has tapered surfaces 134 which terminatein apex 136. As roller 114 rotates, the tapered surfaces 134 capture twofibers 138 which ride the surfaces to apex 136. As shown in FIG. 5, apex132 on bar 116 and apex 136 on bar 118 coincide to press all four fibersinto contact with each other. This contact area is identified by numeral140 in FIG. 6. Spacers 102 and 104 have horizontal ridges or grooves 142on their sides, shown in FIG. 5, to keep the fibers 130, and 138, spacedand parallel to provide four fiber segments 28. These spacers areindicated by dashed lines in FIG. 6 to show their relationship with theZ segments 28 and the contact area 140 between them.

The Z fiber insert station 34 in FIG. 1 is partially shown in FIG. 7with the X-Y array shown below it. A plurality of rectangular guides 144is positioned with a guide over each X-Y square across the width of thearray. A 24 inch wide array with 3/8 inch openings has a row of 64guides. A string of Z segments 28 feeds through each guide and a Zsegment is pushed into each X-Y square in its row as the square movespast the guide. After the Z segment has been inserted, it is cut fromthe string by cutting means 146.

The apparatus for pushing Z segments 28 into the X-Y array includes anendless belt 148 rotated by powered roller 150. Attached to this beltare spaced mover rods 152 extending horizontally. Each guide has avertical slot 154 through which a finger 156 on each rod 152 extends toengage a Z segment. As belt 148 moves rod 152 downwardly, the fingers156 move segments 28 downwardly. As the rods 152 pass around roller 150the fingers 156 free themselves from the segments 28 which momentarilystop their downward movement to permit the lowermost segment to besevered and the X-Y array move forward for the next X-Y square to befilled.

In the preferred mode as previously noted, there is continuous non-stopmovement of the X-Y and X-Y-Z array, and foam material. FIG. 7a showsthe apparatus for moving the Z insertion mechanism at each Z fiberinsertion station 34, described above, longitudinally at the samevelocity as the X-Y array during the vertical Z insertion stroke forinserting the Z segments 28 into the X-Y array. The Z fiber insertionmechanism at 34 and described above is mounted on linear bearings 157for limited slidable back and forth longitudinal movement on ahorizontal rod 159 mounted at opposite ends on brackets 161 supported onthe fixed member 66 on the machine frame. Such longitudinal back andforth movement is for a short distance in each direction.

Longitudinal reciprocating movement to the Z fiber mechanism at 34 isimparted by the rise and fall of the lobes 163 on a cam 165 which isactuated by a shaft 167 mounted on the machine frame 68, and a piniongear 169, which in turn is driven from a rack 171 attached to eachlongitudinally movable side panel or frame 72.

The Z insertion mechanism at 34 is mounted for longitudinal motion inresponse to rotation of cam 165 by means of a pivotally mounted linkage173, one arm 175 of which is pivotally connected at 177 to the rear ofvertically supported member 179 of the Z insertion mechanism 34. Arm 175is also pivotally mounted at 181 at its outer end to a second arm 183 ofthe linkage 173, arm 183 being in turn pivotally mounted at 185intermediate its ends on the machine frame member 66. The lower end ofarm 183 carriers a guide roller or cam follower 187 in contact with theperiphery of cam 165.

The guide roller 187 is maintained in contact with the cam surface bymeans of a spring 189 connected at one end to a fixed bracket 191 and atits opposite end is connected at 193 to the lower end of support member179 of the Z insertion mechanism 34, below the pivotal connection 177 oflink arm 175 with support member 179. The spring 189 is biased in adirection urging the Z insertion mechanism 34 longitudinally to the leftin FIG. 7a, thus maintaining guide roller 187 in contact with theperiphery of cam 165, through the pivotal linkage 173.

Thus, as the side panel 72 advances the X-Y array to the right, viewingFIG. 7a, the gear rack 171 on the side panel turns the pinion gear 169,causing clockwise rotation of cam 165, and causing the Z insertionmechanism at 34 to advance in the same longitudinal direction as the X-Yarray. Cam 165 is designed so that such longitudinal movement of the Zinsertion mechanism is at the same velocity as the X-Y array is moving,as the roller 187 moves to the adjacent lobe or high spot 163 on thecam. Accordingly, there is no relative longitudinal movement between theZ fiber groups 28 and the X-Y array during Z fiber filament insertioninto one row of openings in the X-Y array, and cut-off, as describedabove. As the cam continues to rotate clockwise, the roller 187 moves tothe low portion 195 of cam 165, causing the spring 189 to quicklyretract the Z insertion mechanism to the left, viewing FIG. 7a, thusreturning the Z insertion mechanism at 34 to its original longitudinalposition or station for the start of the next Z fiber insertion cyclefor inserting the Z fibers into the next row of openings in the X-Yarray. With 3/8" openings provided by each X-Y square across the widthof the X-Y array, the Z insertion mechanism would be retractedapproximately 3/8" each time for the start of successive Z fiberinsertion cycles in order to fill all of the X-Y squares of the arraywith Z fibers, when a single Z fiber insertion mechanism is employed.Hence, the Z fibers or filaments are thus inserted into the continuouslymoving X-Y array "on the fly."

Although it is possible to insert Z filaments into the X-Y array whilethe X-Y array is moving relative to the Z insertion mechanism at 34 inthe continuous machine by having the vertical Z insertion velocity highrelative to the longitudinal array speed, increased reliability of Zfiber insertion is obtained by moving the Z insertion mechanismlongitudinally at the same velocity as the X-Y array during the verticalZ fiber insertion stroke, as described above.

In preferred practice, two or more Z fiber insertion devices similar tothose shown in FIGS. 7 and 7a are utilized, suitably longitudinallyspaced along the machine. If two such devices are used, the first deviceor unit would be located so as to install all odd numbered rows of Zfibers into the X-Y array, and the second unit located so as to installall even numbered rows of Z fibers into the X-Y array. If three Z fiberinserter units are used, they would be spaced longitudinally along themachine so that the first unit would install all Z fibers into rows 1,4, 7, 10 etc., of the X-Y array; the second unit, rows 2, 5, 8, 11,etc., of the X-Y array; and the third unit, rows 3, 6, 9, 12, etc. ofthe X-Y array.

FIG. 8 is a fragmentary isometric view of a Z segment inserted in an X-Yarray. In this illustration only two vertically spaced X-Y squares areshown. A Z segment 28 is shown, partially in phantom lines, extendingthrough the array. Each of the Z strands parallel legs 158, 160, 162,164 are in the intersecting corners of the X-Y fibers and may be bondedreadily to these corners, if desired. The upper and lower portions,shown in phantom lines, tapering and terminating in the upper and lowercontact areas 140 are cut and removed after the foaming operation hasbeen completed and the foam insulation partially cured. Preferably theseends are exposed beyond the foam so that they might be bonded toadjacent slabs of insulation, liner faces or tank or hull structure.

Adjacent Z segments are inserted into adjacent X-Y squares with their Zstrand parallel legs also extending between X-Y layers at their cornersof intersection. Thus it can be seen that each intersecting corner hasfour Z fibers contacting it. This provides excellent tensile strengththroughout the thickness of the insulation, resisting rupture in theevent of leakage of liquid natural gas into the foam.

While certain exemplary embodiments of this invention have beendescribed above and shown in the accompanying drawings, it is to beunderstood that such embodiments are merely illustrative of, and notrestrictive on, the broad invention and that we do not desire to belimited in our invention to the specific dimensions, constructions orarrangements shown and described since various other obviousmodifications may occur to persons having ordinary skill in the art.

What is claimed is:
 1. Apparatus for continuously formingthree-dimensional filament reinforced foam insulation, comprising meansfor extending a plurality of continuous first layers of spaced X fibersin a longitudinal direction, said first layers being spaced verticallyfrom each other, means for extending a plurality of second layers ofspaced Y fibers in a transverse direction, said second layers beingspaced vertically from each other, and forming an X-Y array, meansoperatively associated with both of said extending means, forcontinuously moving said layers of X and Y fibers together in a path oftravel in a longitudinal direction, means for inserting Z fibers throughsaid layers to form an X-Y-Z array during said longitudinal movement ofsaid layers of X and Y fibers, and means for foaming an insulationmaterial through said array during continuous movement of said X-Y-Zarray in a longitudinal direction.
 2. Apparatus as defined in claim 1,said means for extending a plurality of second layers of spaced Y fibersin a transverse direction including side members positioned in alongitudinal direction and means for lacing said Y fibers between saidopposite side members.
 3. Apparatus as defined in claim 1, said meansfor inserting Z fibers through said layers of X and Y fibers including aZ fiber insertion device for inserting one row of Z fibers into said X-Yarray, means for advancing said device in a longitudinal direction atthe same velocity as said X-Y array during said insertion of said row ofZ fibers into said X-Y array, and means for retracting said devicelongitudinally for similarly inserting another row of Z fibers into saidX-Y array.
 4. Apparatus as defined in claim 3, including a plurality ofsaid Z fiber insertion devices, said devices being spaced longitudinallyalong said X-Y array, the respective Z fiber insertion devices insertingalternate rows of Z fibers into said X-Y array.
 5. Apparatus as definedin claim 3, said means for foaming an insulation material through saidarray including moving belt means positioned beneath thethree-dimensional X-Y-Z array, means for synchronously moving said beltmeans in the same direction and at the same velocity as said X-Y-Z arrayand into close proximity thereto, and means for discharging the foamonto said moving belt means and permitting said foam to pass upwardlythrough said X-Y-Z array.
 6. Apparatus as defined in claim 1, said meansfor foaming an insulation material through said array including movingbelt means positioned beneath the three-dimensional X-Y-Z array, meansfor synchronously moving said belt means in the same direction and atthe same velocity as said X-Y-Z array and into close proximity thereto,and means for discharging the foam onto said moving belt means andpermitting said foam to pass upwardly through said X-Y-Z array.